1. Field of the Invention
The present invention relates to an apparatus management unit that transmits data of a connected apparatus to a centralized management unit and manages the apparatus based on apparatus management data transmitted from the centralized management unit. Moreover, the present invention relates to an apparatus management system that manages a plurality of apparatuses via a network by use of a centralized management unit.
2. Description of the Related Art
Japanese Laid-open Patent Application No. H4-318731 proposes an apparatus management unit connected to a centralized management unit via the public telephone line. The apparatus management unit receives parameters associated with connection control such as the telephone number of the centralized management unit and the identification number of an apparatus from the centralized management unit. Japanese Laid-open Patent Application No. H4-318859 proposes an apparatus management unit that, when something is wrong with a connected copying machine, stops the operation of the copying machine in accordance with an instruction from a centralized management unit.
Examples of the system in which a centralized management unit and an apparatus management unit are connected as described above include not only the system in which these units are connected by use of the public telephone line but also a system that performs communication by use of the Internet and a radio communication system that uses a PHS (Personal Handy Phone System) or a cellular phone as a terminal unit with the diversification of the communication technology.
In a system that performs data communication between terminals by use of the public telephone line, data is transmitted and received substantially in real time because the line is occupied for the data transmission and reception. On the contrary, a system that transmits and receives data as packets between an apparatus management unit and a centralized management unit like electric mails using the Internet is inferior to the system using the public telephone line in real-time data transmission and reception, because the packets are delivered to the destination address by being transferred in a bucket brigade manner. That is, there is a possibility that the arrival of a mail at the destination address is delayed, for example, because of a trouble on the transfer path.
In an apparatus management system that manages apparatuses connected to a plurality of apparatus management units by transmitting and receiving apparatus management data between a centralized management unit and the apparatus management units, there are cases where apparatus management data has already become obsolete when it arrives because of a delay in arrival of the mail (apparatus management data) from the centralized management unit at the apparatus management unit. In such cases, if the received apparatus management data is used for management, the apparatus will be managed inappropriately, so that the condition of the apparatus can become worse.